First All grain batch last night. I trusted beersmith and ended up with 4 gallons of pre boil wort. It told me 20.31 qt for mash on and 8.13 at mash out. I learned something. If I want it done right I should probbly check calculations long hand rather then trust the computer programs all the time. Anyways I added more water to sparge a second time and got my volume up to the 6 gallons + approx I wanted pre boil. I still ended up with only a 4.5 gallon post boil batch which is bubbling quite nice this morning. I have a problem of efficiencies. 1.068 pre boil and 1.084 post boil 4.5 post boil volume and approx 6.25 pre boil with a 16.25lb grain bill. My math said 70% the calculators said 75-77%. Which is it?